Demand assigned multiple access (DAMA) devices are installed on shore and on board U.S. Navy ships to improve utilization of UHF satellite communication channels. A DAMA device is a communications multiplexer that allocates time slots to specified UHF channel's circuits to improve communication data throughput. One DAMA device that has been used extensively is the TD-1271B/U ("1271") DAMA device manufactured by Motorola Corporation. The 1271 DAMA device sends and receives 32 byte blocks of data at 480 kilo bits per second (kbs) with no handshaking. Every 1.386 seconds two 32 byte blocks are sent and one 32 byte block is received.
Although the 1271 DAMA device has automatic control capabilities (i.e., a high-speed serial communication port), the current mode of operating the 1271 DAMA device is the distributed control (DC) mode. In the DC mode, access to the time slots are made locally at each 1271. No central controller is required other than to provide timing. The disadvantage of this mode is that there is no central point of control, there is no communications privacy, and there are constant key problems.
Thus, there is a need for a computer controller for communicating with a plurality of DAMA devices (e.g., 1271 DAMA devices) via their provided automatic control port in order to improve operating efficiency of the communication system serviced by the devices. Accordingly, it is an object of the present invention to provide an interface for a computer to communicate with one or more DAMA devices via the DAMA devices' provided automatic control port. Another object of the present invention is to provide a DAMA controller interface that is adapted to the data transfer characteristics of the DAMA devices' automatic control port. A further object of the present invention is to provide a DAMA controller interface that may be built from readily available circuit components. Still another object of the present invention is to provide a computer controller interface for a plurality of DAMA devices such that the computer used is a PC/AT type computer.